What is the most appropriate approach to managing bone health in a 77-year-old female with osteoporosis, osteoarthritis, and hypertension, who has been on abaloparatide (abaloparatide) for 2 years after a hip fracture and has shown improved bone mineral density?

Management of Bone Health After Abaloparatide Therapy

The most appropriate approach to management of bone health in this 77-year-old female patient who has completed 2 years of abaloparatide therapy is to stop abaloparatide and start alendronate. 1

Rationale for Transitioning to Antiresorptive Therapy

Abaloparatide is an anabolic agent that has successfully improved this patient's bone mineral density (BMD) over the 2-year treatment period. However, there are several key reasons to transition to an antiresorptive agent now:

1. Duration limitations: Anabolic agents like abaloparatide have a recommended treatment duration of 18-24 months due to safety concerns with prolonged use 2

2. Sequential therapy approach: The standard approach after completing a course of anabolic therapy is to transition to an antiresorptive agent to maintain and potentially further improve BMD gains 1

3. Evidence of efficacy: The ACTIVExtend trial demonstrated that sequential treatment with abaloparatide followed by alendronate maintained and even enhanced BMD improvements 3

Evidence Supporting This Approach

The patient has shown a positive response to abaloparatide therapy with improvements in T-scores at all measured sites:

• Hip: -2.9 → -2.7
• Femoral neck: -2.7 → -2.5
• Spine: -3.0 → -2.5

These improvements indicate treatment success, but continuing abaloparatide beyond 2 years is not recommended based on:

1. Safety concerns: The FDA label for abaloparatide notes potential risks with prolonged use, including development of osteosarcoma in animal studies 2

2. Sequential therapy evidence: The ACTIVExtend trial showed that patients who transitioned from abaloparatide to alendronate maintained fracture risk reduction across all baseline risk subgroups 3

3. Guideline recommendations: Current osteoporosis treatment guidelines recommend transitioning to an antiresorptive agent after completing a course of anabolic therapy 1

Why Alendronate is the Preferred Next Step

Alendronate is the most appropriate antiresorptive agent for this patient because:

1. Strong evidence base: Alendronate has been extensively studied in sequential therapy after anabolic agents 1

2. Fracture risk reduction: Alendronate reduces vertebral, nonvertebral, and hip fractures in women with osteoporosis 1

3. Specific sequential therapy data: The ACTIVExtend trial specifically evaluated the abaloparatide-to-alendronate sequence and found significant benefits in fracture reduction and BMD maintenance 4, 3

4. First-line recommendation: The American College of Physicians recommends oral alendronate as the most appropriate treatment for postmenopausal osteoporosis with hip fracture 1

Implementation Considerations

When initiating alendronate therapy:

• Dosing: Standard dosing is 70 mg weekly
• Administration: Take on an empty stomach with a full glass of water, remain upright for 30-60 minutes
• Supplementation: Continue calcium (1000-1200 mg daily) and vitamin D (800-1000 IU daily) supplementation 1
• Monitoring: Reassess fracture risk after 5 years of bisphosphonate therapy to determine need for continued treatment 1
• Follow-up BMD: Consider DXA scan in 1-2 years to assess response to alendronate therapy 1

Why Other Options Are Not Appropriate

1. Continuing abaloparatide: Not recommended beyond 2 years due to safety concerns and lack of evidence for extended use 2

2. Switching to teriparatide: Not appropriate as the patient has already received 2 years of anabolic therapy with abaloparatide; switching to another anabolic agent is not supported by evidence 1

3. No further therapy: Inappropriate given the patient's history of hip fracture and current T-scores still in the osteoporotic range (T-score ≤ -2.5), indicating continued high fracture risk 1

Special Considerations for Elderly Patients

For this 77-year-old patient:

• The ACTIVExtend study specifically analyzed outcomes in women ≥80 years and found that sequential abaloparatide-alendronate therapy was well-tolerated and effective 4
• Elderly patients have higher baseline fracture risk and may particularly benefit from continued therapy after completing anabolic treatment 5
• Monitor for potential side effects of alendronate, including gastrointestinal symptoms, and ensure proper administration technique to minimize risks 1